Tuesday, April 20, 2010

1. New Zealand
A few engineers in New Zealand want to exploit their blessed natural environment to constitute generation mixes that provide 100% renewable electricity system for their country. The mixes will be 53~60% hydro, 22~25% wind, 12~14% geothermal, 0~12% additional peaking plant, 0.8~0.9% wood thermal and 0.2~0.3% biogas generation.
Renewable energy's intermittency (0~12% of the generation mixes) is overcome by suggested peaking generation options: demand-side management (so-called "load shifting"), biomass-derived gas-fired generation, pumped storage hydro generation, and additional conventional hydro generation. They are promptly dispatchable and easily applicable in New Zealand's natural environment.
They conclude this 100% renewable electricity system can replace the current system and displace 32% of fossil-fueled thermal generation.

2. Denmark
New Zealand's case is similar to North Carolina's plan, which I introduced in http://bit.ly/bx1XUv. Both have renewable peak generation options and do not reduce electricity demand drastically.
Denmark's ambition is different in that the authors assume a painful cut in energy demand. It is not electricity demand only. It is total energy demand. The 442 PJ (petajoule; 1015 J) of their proposed energy demand in 2050 is 53% below 950 PJ of the Business-As-Usual plan in the same year.
The reduced energy demand is supplied by biomass (straw, wood, biomass to biogas, slurry fibre fraction, energy crops, biodegradable waste, and algae), wind, PV, wave, and solar thermal power.
Denmark's transport sector reduces energy demand by policies such as road-pricing, urban planning, deployment of electric train and vehicles, etc.

3. Thoughts: Unfair?
Both plans depend on each country's natural endowments. New Zealand's hydroenergy and Denmark's biomass are good examples. How can other countries with limited natural renewable resources achieve 100% renewable energy/electricity system?